Abstract: Nonlinear finite element analysis of the steel truss girder in the fabricated steel structure of housing system was studied in this paper． Finite element models of steel truss girders were established with five different spans and different chord sizes． It was compared the load -displacement curves of the analysis results from different girders，the ultimate bearing capacity and deformation characteristic of the steel truss girder in the fabricated steel structure were studied． The plastic zone mainly occurs at midspan chord when the girder damaged，and webs at a relatively small force damaged after the chord，which could meet the design requirements ofstrong shear and weak bending． The big difference between yield load and ultimate load makes the member have certain safety margin space．